The present disclosure relates to a part, for example a turbine component such as a bladed disk (BLISK), compressor blade, or turbine blade, manufactured using additive manufacturing processes.
An aircraft gas turbine engine or jet engine draws in and compresses air with an axial-flow compressor, mixes the compressed air with fuel, burns the mixture, and expels the combustion gases through an axial-flow turbine to power a compressor. The compressor and turbine, each include a disk with blades projecting from its periphery. The disk turns rapidly on a shaft.
There are two approaches to the assembly of the blades and disk of an axial-flow compressor or axial-flow turbine. In one approach, the component is made by forging the disk as a single piece with slots at the periphery. A plurality of blades are mechanically affixed to the disk, using a dovetail attachment or other structure. Typically, the blades are individually cast or forged to shape with a root section termed a “dovetail” or “fir tree” that fits into slots formed in the disk. Slots that resemble an inverted ‘v’ are cut into the rim of a disk; one for every blade. The blades have corresponding features that interlock with the slots in the disk. Assembly is completed by sliding the sections of the blades into the slots in the disk. When the disk spins at high speeds the centrifugal load of the blade is transferred to the disk through these ‘dovetail’ or ‘fir tree’ arrangements. Due to the complex shape of the contact areas between the blades and disk, the contact stress limit requires additional area (axial engagement) for a robust design. If a blade does not fit properly, fails, or is damaged during service, it may be readily replaced by reversing the assembly procedure to remove the blade, and providing a new blade.
In the other approach, the blades are integral with the disk. The second approach having an integral blade/disk structure, called a “blisk” in the art, is favored in those situations where it may be used because the mechanical attachment of the first approach may add a substantial amount of weight to the structure. More specifically, the blisk approach to manufacturing offers the potential for increased performance through reduced weight. Such an article can be cast or forged as a large disk with an excess of metal at the periphery. The blades may then be machined from the excess metal, thus integrally attached to the disk. The final product is expensive to produce, as it requires extensive high-precision machining operations. An error in machining even one of the blades may result in rejection and scrapping of the entire BLISK or an expensive and time consuming repair.
Turbine blisks with uncooled blades have been fielded on commercial products. However, without cooling they are limited to very low temperature operation. Current turbine weight reduction efforts have focused on the use of advanced materials such as CMC's or TiAl's in conventional blade and disk designs. While ceramic matrix materials (CMC's) enable rotating component weight reductions, CMC technology still faces the challenges of manufacturability, interface with a metal components, life and cost.
There is thus a desire for an improved bladed disk, or blisk design, and method of manufacture and/or repair, wherein the article includes internal cooling features. The present disclosure fulfills this need, and further provides related advantages.
These and other shortcomings of the prior art are addressed by the present disclosure, which provides a power generation system.